First Synthesis of Optically Pure Propargylic N-Hydroxylamines by Direct, Highly Diastereoselective Addition of Terminal Alkynes to Nitrones We thank the ETH, Roche Research Foundation, the Swiss National Science Foundation, Merck, and Aventis for their generous support.

In situ generation of nucleophilic alkynilides by using substoichiometric amounts of Zn(OTf)2 (OTf = trifluoromethanesulfonate) followed by removal of the chiral auxiliary enables the direct use of a wide range of terminal acetylenes in the synthesis of optically pure propargylic N-hydroxylamines (see scheme).